No 2 (2017)

Articles

Processes occurring in an engine with an unconventional duty cycle

Berdnikov A.A.

Abstract

An internal combustion engine is a thermal machine that converts thermal energy into mechanical energy. Currently, the existing engines operate in cycles of Otto, Diesel and Sabate-Trinkler. Such cycles are usually called traditional. As is known, traditional internal combustion engines do not have a high coefficient of efficiency due to large losses of heat with exhaust gases, heat removal to the cooling system, etc. The reserves of increasing the efficiency are very high. However, modern engine building has reached a high level and further improvement of the working process in traditional cycles is already ineffective. The article proposes a non-traditional seven-stroke internal combustion engine and examines the processes occurring in the cylinders of such an engine. In the main cylinder of the engine, the working cycle proceeds as in a traditional four-stroke internal combustion engine: at the first stroke, there is an intake, on the second stroke - compression, on the third - combustion and operating stroke, but in the fourth cycle the exhaust gases are not diverted from the cylinder, but are sent to an additional cylinder - there is a continued expansion of gases (operating stroke). At the fifth bar, the exhaust gases are compressed in an additional cylinder, and water is supplied at the end of the compression. Selecting heat from the heated parts of the cylinder-piston group and compressed gases, the water evaporates, and the expanding steam performs useful work (the sixth stroke is the operating stroke). At the seventh stroke, the piston moves to the top dead center, displacing the steam with the exhaust gases. Preliminary calculations showed that the maximum pressure of the seven-cycle operating cycle of the internal combustion engine can reach up to 20 MPa, this increases the power and fuel economy of the engine. The injection of water somewhat reduces the maximum cycle temperature and the toxicity of the exhaust gases. Such advantages give reason for the implementation of the working cycle of the internal combustion engine in a seven-cycle scheme.
Izvestiya MGTU MAMI. 2017;(2):2-7
pages 2-7 views

Anthropomorphic foot mock-up, to assess the trauma safety of the crew of auto armored vehicles with mine explosion

Gavrilov E.V.

Abstract

The article presents the results of development and testing of an anthropomorphic foot mock-up, which allows to determine the leg safety in case of mine explosion. As the statistics show, the legs of the crew of auto armored vehicles, as well as the driver and passengers of special protected civilian vehicles, are subject to a strong dynamic impact with a mine explosion, resulting in an increased level of injuries to this part of the body. When developing a protected technique, special attention is paid to leg injuries. Since the anthropomorphic measuring dummies used in the tests for mine explosion are limited, and it is necessary to determine the trauma safety of a large number of people, it was decided to develop an anthropomorphic foot mock-up. The anthropomorphic mock-up of the leg consists of the M2A-02 carrier module with the M3A-01 bushing adapter, the 723/8 foot, the calf shank spring, and the weight cylinder that replaces the missing shank mass and half the hip mass. To determine the axial force in the shin, a special motion sensor is used. According to the measured compression and the existing spring stiffness, a peak axial force is calculated. The anthropomorphic mock-up of the leg was calibrated on a special coprode stand for discharge. The discharge from various heights from 0.46 m to 2.5 m was made on different surfaces - sand and steel with a thickness of 8 mm. Also, a leg was dropped, shod in a statutory boot. After the calibration, the device was used in full-scale tests by undermining a special civil protected vehicle to determine the trauma safety of the driver's and passengers' legs. According to the results of the work, it was concluded that the foot mock-up can be used for testing special civil protected vehicles, as well as for armored vehicles with mine explosion.
Izvestiya MGTU MAMI. 2017;(2):8-15
pages 8-15 views

Development of a mathematical model of an articulated cross-country vehicle for the Arctic zones of the Russian Federation, regions of the Far North and the Far East

Gorelov V.A., Kartashov A.B., Kovtun K.I., Komissarov A.I.

Abstract

Currently Bauman Moscow State Technical University, PJSC "KAMAZ" and Moscow Polytechnic University are working on the creation of an articulated-cross-country vehicle on the basis of serial units and aggregates of KAMAZ vehicles, the main design feature of which is the joint junction. Depending on the design, single-stage, two-stage and three-stage hinges are distinguished, allowing to realize rotation around the vertical, longitudinal and transverse axis of the junction joint. The article deals with the influence of the angle of inclination of the pivot pin (vertical axis) and the introduction of an additional (longitudinal) degree of freedom in a single-junction joint at the stabilizing moment. For this purpose, a mathematical model of an articulated cross-country vehicle was developed in the environment of the automated analysis of the dynamics of systems of bodies. The description of the main nodes, systems and control algorithms of the developed all-terrain vehicle is given. During the simulation, the movement of the vehicle was investigated when performing the typical maneuver with different versions of the joint unit with simultaneous registration of the folding angle of the frame sections. Based on the studies performed and analysis of their results, the following conclusions are formulated: the stabilizing moment, sufficient to return the frame sections to the initial position, arises only at large angles of inclination of the pivot pin, and the introduction of an additional degree of freedom in the junction node substantially reduces the stabilizing moment. Further development of the mathematical model will allow at the design stage to estimate such operational indicators of the all-terrain vehicle being developed as smooth running, profile cross-country, traction and braking dynamics under different road conditions.
Izvestiya MGTU MAMI. 2017;(2):16-24
pages 16-24 views

The hydrodifferential rectifier of the moment of inertial automatic transmission of mobile machines

Greben'kov D.V.

Abstract

The article considers the possibility of using torque in the inertial-pulse automatic transmissions of a hydrodifferential rectifier, in the design of which hydraulic machines are used as free-wheel clutches. Unlike mechanical freewheel clutches, where the weakest of their links are the jamming bodies, in the proposed construction the jammed body is hydraulic fluid, which allows to eliminate the above-mentioned drawback and reduce wear. A kinematic scheme of inertial transmission with a hydrodifferential torque rectifier is given and the working process is described on three characteristic operating modes: stop, torque and direct transmission. Dependences for calculation of basic parameters of hydraulic clutches of a free wheel are given, and also theoretical and experimental results of researches of working capacity of the inertial hydrodifferential torque transformer are presented. An analysis of the results showed that with increasing internal leakage of the working fluid, which increase as a result of wear of the hydrodifferential torque rectifier, the power and torque on the shaft of the hydraulic machine will decrease, which in turn will decrease the efficiency of the hydrodifferential rectifier. The analysis of the results showed that at the beginning of operation the efficiency of the hydrodifferential rectifier is about 93% in the entire operating range. During operation, the efficiency of transmission decreases linearly and at a radial gap of 300 ÷ 350 μm is only 68 ÷ 63%. With further deterioration (radial clearance 350 ÷ 400 μm), the efficiency is practically not reduced. This indicates that the hydrodifferential rectifier of the torque has completely worn out and its replacement is required.
Izvestiya MGTU MAMI. 2017;(2):25-30
pages 25-30 views

Algorithm for navigation of ground-based transport-technological facilities on the basis of integrated inertial-satellite navigation and odometer data

Novikov P.V., Sheypak A.A., Gerdi V.N., Novikov V.V., Enin V.N.

Abstract

The dynamic development of navigation technologies has led to the emergence of practical applications for the solution of the problem of navigation of ground transport and technological facilities (GTTF). The most promising way of solving the navigation problem of GTTF is the creation of integrated inertial-satellite navigation systems. For a long period of time, the widespread use of navigation systems for transport applications was constrained by their high cost. The appearance of low-cost microelectromechanical (MEMS) inertial sensors on the market of navigation equipment provided the technological basis for the creation of small-scale inertial-satellite navigation systems. For transport applications, integrated inertial-satellite are integrated with additional information sensors, which include the odometer. Implementation of integrated systems is impeded by massively high level of intrinsic errors in MEMS sensors, as well as by the low accuracy of determining navigational parameters in the zone where the satellite signal of the satellite navigation systems is not stable. It is obvious that the development of methods for processing measurement information and the synthesis of specialized algorithms that ensure the accuracy of navigation systems GTTF is an urgent scientific task. In this paper, a schematic and technical solution for constructing an integrated inertial-satellite navigation systems with an integrated odometer sensor is presented and justified. A specialized navigation algorithm is developed that provides an integrated navigation solution for data coming from heterogeneous sources of measurements. A detailed functional diagram of the algorithm is given. A set of functional criteria for the quality and reliability of the navigation solution is defined. Correction algorithms for the main kinematic parameters of the trajectory motion of the GTTF - the true course angle, the location coordinates, the velocity vector components, are developed. The developed algorithm is invariant to the type of inertial sensors and in this sense is unified. Performance was confirmed by the results of full-scale tests of the navigation system of a forklift truck carrying out freight traffic on the territory of the seaport.
Izvestiya MGTU MAMI. 2017;(2):31-39
pages 31-39 views

Static characteristics of the pneumatic power amplifier "nozzle-shutter"

Pil'gunov V.N., Efremova K.D.

Abstract

The results of an experimental study of the mechanic-pneumatic converter "nozzle-shutter" and the pneumatic power amplifier created on its basis are presented. Such devices can be used in the design of damping systems for a multi-bearing oscillatory system of a special-purpose vehicle intended for the transport of "delicate" goods. The algorithm for controlling the adaptive air-hydraulic spring is rather complicated and it may require expensive hydraulic equipment with electromagnetic proportional control for its implementation. A possible alternative to such equipment are pneumatic devices built on the basis of adjustable throttles "nozzle-shutter". The installation on board of vehicles on wheeled or caterpillar tracks of cargo beams or platforms with a load fixed to them may be associated with the need for their stabilization in a horizontal position in the case of a shift in the center of gravity of the cargo relative to the vertical axis. Such a problem can be solved using differential hydraulic cylinders with a cross-connection of their piston and rod cavities, and compensation for the difference in feed rates and costs should be ensured by means of pneumatic-hydraulic accumulators. In both cases, a pressure control system is required in the gas cavities of an air-hydraulic spring or an air-hydraulic accumulator, which can be implemented on the basis of a mechanic-pneumatic converter or a pneumatic power amplifier. In pneumatic continuous control systems used in mobile equipment, the directing and distribution subsystem is usually built on the basis of pneumatic throttling valves with electromagnetic proportional control. Due to the limited power of proportional electromagnets, the creation of such pneumatic directional valves is limited by their throughput. In the throttling pneumatic distributors of indirect action, the replacement of the power amplifier of the spool type with the power amplifier "nozzle-shutter" improves the dynamic characteristics of the distributor and reduces its cost. It is possible to use the obtained experimental flow-control, adjustment and power characteristics presented in dimensionless parameters when calculating the adaptive suspension of multi-axis transport systems and the cargo platforms stabilized on the horizon.
Izvestiya MGTU MAMI. 2017;(2):40-48
pages 40-48 views

Perspectives of using humidification subsystems for air conditioning in transport

Merkulov V.I., Popov A.A.

Abstract

With long-term human activity, many factors begin to make a significant influence on fatigue and reduced concentration. The question is even more urgent when it comes to drivers and operators of road construction and agricultural machinery. Work on these modes of transport involves increased danger and additional responsibility for life and health of people. Along with such parameters as ergonomics and optimization of the work and rest regime, the optimal values of the microclimate parameters in the driver's area or the operator of transport equipment play an important role. The microclimate parameters include: pressure, oxygen concentration in air, temperature and humidity. And if there is no need to regulate the oxygen content and pressure in land transport, in contrast to aircraft, and the temperature is regulated by the air conditioning systems of the car, the humidity parameters are not given proper attention. In the conditions of road transport and construction equipment, in areas of low humidity or increased dust generation, a low level of moisture content in conditioned air begins to play a key role in the increased fatigue and the development of drivers chronic diseases. This can be fraught with both a decline in efficiency and economic losses, and the creation of additional dangerous situations for life and health of people. The article discusses and compares the main methods of moisture saturation of dry air, and assesses the acceptability of their implementation in road transport, and conducts typical estimated calculations of changes in system parameters from load conditions. The peculiarities of the application of air humidification in air conditioning systems for ground and air transport are given, a generalized assessment of the methods of moistening, their advantages and disadvantages is made, the most optimal methods of humidifying air are revealed from the point of view of transport technology. For the calculations, the software complex MathCAD was used.
Izvestiya MGTU MAMI. 2017;(2):49-53
pages 49-53 views

The use of hydraulic communication channel in technical systems

Trukhanov K.A.

Abstract

When developing technological systems, it becomes necessary to transmit information over significant distances without the use of traditional means of communication, because they can not be used, for example, in the field of geonavigation when drilling inclined / horizontal wells. One of the possible channels for transmitting information in this area is the hydraulic communication channel (HCC). Therefore, at present, the task of developing an effective method and approach for transmitting information on the HCC becomes urgent. The purpose of this work was to create a mathematical model of the HCC to provide practical recommendations when used in technology to assess the possibility of transmitting information on it without conducting costly field tests. The article presents a mathematical model of the HCC, which is a long hydroline, taking into account the boundary conditions at its input and output from it. The input boundary condition is represented by a piston pump with a crank-and-rod drive mechanism. The output boundary condition is represented by a throttle - a mechanical device capable of overlapping the pass channel in the hydrolysis line, thereby creating pressure pulses through which useful transmitted information is generated over the HCC. The obtained characteristic for the relative instantaneous feed Q is shown as a function of the angle φ of rotation of the pump shaft. A relation is given that establishes the relationship between the area of the opened throttle windows and the angle of rotation of its shaft. Two applied methods for encoding information in technological systems for information transmission are considered and a dependence for the attenuation of the signal amplitude during data transmission over the HCC is given. A mathematical simulation of the system with HCC and the described boundary conditions is performed. The form of the pressure pulse is obtained. Based on the results of the work, conclusions were drawn.
Izvestiya MGTU MAMI. 2017;(2):54-63
pages 54-63 views

Calculation and substantiation of design parameters of automotive mechanical stabilizers of lateral stability with adjustable rigidity

Tyagunov A.E., Kartashov A.B.

Abstract

The safety of the automobile can be characterized by such concepts as maneuverability, controllability and stability of its movement. To improve the controllability and stability of the automobile during the design, a number of different activities are carried out. In particular, from the point of view of design, a stabilizer of lateral stability is installed on almost every vehicle. It is designed to reduce the transverse roll of the sprung part of the automobile caused by movement along a curved path, a strong side wind or a road slope. Thus, in this article we consider a possible application of stabilizers of lateral stability with variable rigidity on high-speed vehicles, together with the suspension of the rear axle, which has "steering up" kinematics. The influence of such a combination on the stability of the vehicle's motion and its controllability is considered based on the basic principles of the theory of motion of wheeled vehicles. And most importantly, the developed technique for calculating the mechanical stabilizer of lateral stability with variable stiffness is presented, which in turn assumes the use of the finite element method for calculating the stiffness of structural elements of the stabilizer. It should be emphasized that stabilizers of this design are used mainly for racing cars. But the method of calculating them in the article can be shifted to more complex designs used in the serial automotive industry. It can be stabilizers of lateral stability with the built in hydraulic, pneumatic or electromechanical elements, allowing to carry out adjustment of torsional rigidity of the stabilizer. This article is one of the few in the Russian-language literature that covers the question of the methods of calculating stabilizers of lateral stability with variable rigidity.
Izvestiya MGTU MAMI. 2017;(2):64-71
pages 64-71 views

Ignition of poor fuel-air mixtures in gasoline-driven ICEs - problems, solutions

Egorushkin E.A., Shabanov A.V., Shabanov A.A.

Abstract

The article deals with the development of technologies in the field of improving the organization of the combustion process in internal combustion engines in order to solve the problem of protecting the environment and increasing the efficiency of fuel resources. The carried out analysis has shown the increased interest of researchers and automotive experts in the problem of ignition of poor mixtures in ICE by the method of fuel-air charge separation in the combustion chamber. The directions of intensification of combustion of poor mixtures in internal combustion engines are considered due to application of various methods of fuel-air charge separation in the combustion chamber of internal combustion engines. Combustion of poor mixtures ensures low emissions of harmful substances with exhaust gases of the internal combustion engine and improved fuel economy. The advantage of an internal combustion engine using poor fuel-air mixtures is its operation with little or no charge throttling at the inlet. At the same time, fuel consumption and, correspondingly, CO2 emissions are reduced to 25%. Low concentrations of harmful emissions also reduce the efficiency requirements of the neutralizer. The process of combustion of poor mixtures is carried out due to the technologies of direct electronic fuel injection into the combustion chamber under high pressure and catalytic neutralization of combustion products of poor mixtures. Effective combustion of fuel-air mixtures is achieved with an excess air factor of less than 1.7. The article also contains the results of tests of the prechamber-flare internal combustion engine, which showed the possibility of using qualitative engine power regulation due to work on poor mixtures and a significant reduction in emissions of harmful substances with exhaust gases. It is shown that the use of an electronic ignition system with an increased discharge energy and a system of homogeneous mixture formation leads to an intensification of combustion of poor mixtures in the internal combustion engine, and allows the engine to operate at superhigh mixtures with an air excess factor of 3.5 with stable combustion of fuel-air mixtures.
Izvestiya MGTU MAMI. 2017;(2):72-77
pages 72-77 views

The magnitude of frictional clutch moment during the start acceleration of automobile or tractor

Sharipov V.M., Dmitriev M.I., Klimova E.V.

Abstract

At the present time there are still works where it is assumed that the frictional clutch moment in dynamics is greater than in static. In reality, this is not the case. It is shown that for existing types of friction linings (based on asbestos, asbestos-free polymer or powdered sintered), working in a dry environment with cast iron, the sliding friction coefficient is 0.23 ... 0.27. In this case, its value is 60 ... 70% of the coefficient of static friction. For friction clutches operating in oil, the value of the static coefficient of friction in the contact of the closed clutch discs of the disconnected gear is 1.7 ... 2.2 larger than the dynamic friction coefficient of the friction clutch of the gear involved. These data were obtained experimentally for friction discs with sintered powdered material MK-5 on a copper basis, Shadef on an iron basis, as well as HS43 and HS09 (Hoerbiger, Austria) on a copper basis. This confirms that frictional clutch moment in the dynamics is always less than in the static. The oscillograms with the results of the process of dispersal from the place of various tractor units are given, from which it follows that in most cases of start acceleration of the vehicle the clutch ends its slipping until it is fully turned on. Consequently, in most cases start, the acceleration of the vehicle does not use the maximum friction torque of the clutch in the dynamics, which, as was shown above, is always less than the frictional clutch in static.
Izvestiya MGTU MAMI. 2017;(2):78-83
pages 78-83 views

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